Catalytic conversion of hydrocarbons



-tally has been of chromium oxide.

Patented Apr. 24, 1945 CATALYTIC CONVERSION OF HYDROCARBONS Robert E.Burk and Everett 0. Hughes, Cleveland Heights, Ohio, assignors to TheStandard Oil Company, Cleveland, Ohio, a corporation of Ohio N Drawing.original application March 23, 1939, Serial N 0. 263,806. Divided andthis application Decemberv 6, 1939, Serial No. 307,864

8 Claims. (or. 260-668) It has been known for some time that aliphatic.

or nlaphthenic hydrocarbons can be converted into aromatic hydrocarbonsby contact at elevated temperatures with a catalyst, which fundamen-Operation by such catalyst however is under a disadvantage ofencountering deterioration after a relatively short run, andregeneration of the catalyst is beset with practical difficulties, suchcatalyst being very critical. We have now found that superior operationsmay be had, based on catalytic materials of a different source and kindof preparation, in contrast to practices heretofore. The operation isparticularly satisfactory in its high yield and the niniformityof thecatalyst, and its satisfactoriness of regeneration are especiallyoutstanding.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the larly pointed out in the claims, the followingdescription setting forth in detail certain illustrative embodiments ofthe invention, these being indicative however, of but a few of thevarious ways in which the principle of the invention may be employed.

Where catalysts 'are prepared by dumpingthe proportional theoreticalamounts of metal salts and a precipitating hydroxide together as hasbeen the customary procedure heretofore, we find that the catalysts arenon-uniform, and in a given particle at verywide difference incomposition may be found from the outer surface in. This, we have found,is connected with the general tendency of the catalysts to show apoorlysustained behavior and variable regeneration. In contrast withsuch procedure, the present invention, in precipitating a catalyticmaterial provides the precipitant at a rate which at any given moment isshort of that theoretically required for precipitation, and convenientlythe mixing is accomplished by simultaneous feeds of the materials, atsuitable relative rates for such condition, and at the end of themixing, the deficiency of the precipitator is supplied to complete theprecipitation. Furthermore, this manner of formation of catalyticmaterials, is found by us to be particularly advantageous with ironoxide and alumina. Alumina and an oxide of metals of atomic number 26-27are of great practical utility, or for some uses atomic number 26 28,and in some cases the range may be extended as elements of atomic number2528, i. e. manganese, iron, cobalt and nickel. It will be understoodthat there are some peculiarities which distinguish the groupings as wehave just stated foregoing.

' features hereinafter fully described, and particu- As examplesillustrating the process and showmonium hydroxide is dissolved indistilled water at the rate of 665 parts to a make up of 2,000 parts ofwater (which is per cent of the theoretically required ammoniaprecipitant). These solutions are fed at equal rates, by pumping into areaction vessel which has been charged with 120 parts of ammoniumacetate and 4,000 parts of water. After the progressive and simultaneousaddition of the solution of metal salts and solution of ammonila to thereactionvessel, a further addition of parts-of concentrated ammonia in500 parts of water is fed in to finish the precipitation. Theprecipitate is filtered, washed, and dried, and is ready for the furtheroperation which will be described hereinafter. This catalytic materialis a 20:80 mol per cent FezoaAlzoa catalyst, and is' remarkablymniformin composition.

II. Aluminum nitrate and cobalt nitrate are dissolved in distilled waterat the rate of 0.8 mol of aluminum nitrate and 0.2 mol of cobalt nitratewith 2,000 parts by weight of water. Concentrated ammonium hydroxide asabove noted, is also dissolved in distilled water at the'rate of 6.2parts of the ammonia to a make up of 2,000 parts of water (70' per centof the theoretical requirement for a complete precipitation) The twosolutions are fed simultaneouslyand through a period of ten minutes,into a reaction vessel which contains parts of ammonium acetate in 4,000parts of water. The two solutions having been completely fed in,suflicient ammonium hydroxide isadded, like in the foregoing, tocomplete the precipitation, and the precipitate is filtered, washed, anddried.

III. Aluminium nitrate and nickel nitrate are dissolved in water at therate of 0.8 molof aluminum nitrate and 0.2 mol of nickel nitrate to amake up of r 1,420 parts of water. This solution is fed, andat the sametime ammonia gas is fed,

through a period of five minutes, (the ammonia going to 70 per cent ofthe theoretically required precipitate amount), the feeding of thecomponents being to a reaction vessel containing 120.

parts of ammonium acetate to 6,500parts of water. These componentshaving been completely added, the rest of the theoretically requiredamount of ammonia for precipitation is added over a period of two and ahalf minutes. The

precipitate is finally filtered, washed, and dried.

In similar manner as in the foregoing example, an aluminum salt and aniron salt, or an aluminum salt and a cobalt salt, may be advantageouslyprecipitated first with use of ammonia gas and then ammonium hydroxidesolution.

The catalyst thus prepared may be granulated or pelleted, and is placedin a reacting zone with suitable heating means such that the temperatureof the mass may be maintained around 932 F., and preferably notunder 700nor over 1250 F. The pressure may be atmospheric or up to not in excessof about 400 pounds per square inch. To the catalytic material there isthen supplied a hydrocarbon, such as n-hexane, cyclohexane, heptane,octane, etc., or naphthas or distillates from non-benzenoid stocks, forinstance Pennsylvania, Michigan, Kentucky, Mid-Continent,- Ohio, and thelike petroleum. Pennsylvania or Michigan naphtha in the boiling range140420 F. is particularly advantageous. The hydrocarbon is contactedwith the catalyst at a rate of feed depending upon the operatingtemperature, and which in general may be 0.1 to liters of liquid pereach liter of catalyst. With particu lar advantage, the product from thetreating zone may be subjected to a solvent having selectivesolventicity, such as liquid sulphur dioxide or a high boiling amine orhydroxide, and the portion of the product not dissolved by the solvent,may on separation therefrom be re-passed through the catalytic zone.Michigan petroleum naphtha thus subjected to the action of anAlzOa.Fe:Oa catalyst consisting of 80 mol per cent Al and mol per centFe, at a temperature of 932 F. and a flow rate of one and three-fourthsgrams of naphtha per hour per each gram of catalyst, yields a producthaving a Kattwinkel test of 34 per cent and bromine number 11. Again, asimilar naphtha contacted with an AlzOzCoOa catalyst under likeconditions, yielded a product having a Kattwinkel test 30 per cent andbromine number 16.8. It will be understood that the Kattwinkel testrepresents the volume per cent. of a sample of the product absorbed by96 per cent sulphuric acid to which has been added 30 per cent by weightof P205. This percentage represents the totaipercentage of aromatics andunsaturates in the sample tested.

When the catalyst activity declines to an undesirable or predeterminedpoint, the hydrocarbon feed may be shut ofi, and oxygen-containing gas,as air or air diluted with inert gas, may be passed over the catalystwhich may be maintained at elevated temperature. The present aluminacatalysts in fact regenerate particularly well and retain theiractivity. For example, 20:80 iron and aluminum oxide catalyst yielding aproduct, at a, temperature of around 932 F., showing a Kattwinkel testof 42 per cent, after regenerating with air and dissimilar maintainedhave set forth, is especially advantageous from the ease with which acatalyst can be duplicated exactly from batch to batch. Heretofore,vari-- ation of catalysts has been an annoying dim-- obtainable by priorprocedures.

"This application is a division of our application Ser. No. 263,806,filed March 23, 1939, which has become Patent No. 2,270,504.

Other modes of applying the principle of the invention may be employed,change being made as regards the details, described, provided thefeatures stated in any of the following claims, or the equivalent ofsuch, be employed.

We therefore particularly point outand distinctly claim as ourinvention:

1. In a process of aromatizing hydrocarbons, subjecting a non-benzenoidhydrocarbon to a temperature of 700-1250 F. and the action of acontact-mass consisting of oxides characterized by being a driedco-precipitate formed by addi- For illustration,

temperature, on re-feed of the hydrocarbon again showed a Kattwinkeltest of 42 per cent, feed rate being the same as in the first run, andsimilarly on further regeneration.

The feed of the hydrocarbon to the catalytic zone may be diluted toadvantage with hydrogen or the off-gas from the process may be recycledback for this purpose. In some cases steam or hire gas may be used asdiluent. By. returning the hot carbon dioxide formed in regenerating,heat may be also supplied to the catalyst bed.

It is to be noted that the preparation of catalytic masses in accordancewith the manner we tion of first ammonia gas and then ammonium hydroxideto a solution of salts of iron and aluminum, the aluminum oxide being inpredominant proportion.

2. In a process of aromatizing hydrocarbons, subjecting a. non-benzenoidhydrocarbon to a temperature of 700-1250 F. and the action of acontact-mass consisting *df oxides characterized by being a driedco-precipitate formed by addition of first ammonia gas and then ammoniumhydroxide to a solution of salts of cobalt and aluminum, the aluminumoxide being in predominant proportion.

3. In a process of aromatizing hydrocarbons, subjecting a non-benzenoidhydrocarbon to a temperature of 7001250 F. and the action of acontact-mass consisting of oxides characterized by being a driedco-precipitate formed by addi tionof first ammonia, gas and thenammonium hydroxide to a solution of salts of nickel and aluminum, thealuminum oxide being in predominant proportion.

4. In a process of aromatizing hydrocarbons, subjecting a non-benzenoidhydrocarbon to a temperature of 700-1250 F. and the action of acontact-mass consisting of oxides characterized by being a driedco-precipitate formed by addition of first ammonia gas and then ammoniumhydroxide to a solution of salts of aluminum and a metal of the groupconsisting of metals having atomic numbers 26, 27 and 28, the aluminumsulting from the feeding of a solution of salts of said metals andanalkaline precipitant at rates such that there is a deficiency of theprecipitant for completing precipitation of the metals at any givenmoment, and the subsequent subjecting a non-benzenoid hydrocarbon in thepresence of a returned portion of the ofi-gas in the addition of thedeficiency of the precipitant,

the aluminum oxide being in the predominant proportion.

7. In a process of aromatizing hydrocarbons, subjecting a non-benzenoidhydrocarbon in the presence of a returned portion of the off-gas in theprocess to a temperature of 700-l250 F. and the action of a,contact-mass consisting of oxides of nickel and aluminum which oxidesare coprecipitated in a particular uniform relationship resulting fromthe feeding of a solution of salts of said metals and an alkalineprecipitant at rates such that there is a deficiency of the precipitantfor completing precipitation of the metals at given moment, and thesubsequent completing of the precipitation of the metals by the additionof the deficiency of the precipitant, the aluminum oxide being in thepredominant proportion. I Y

8. In a process of aromatizing hydrocarbons, subjecting a non-benzenoidhydrocarbon in the presence of a returned portion of the off-gas in theprocess to a temperature of 700-1250" F. and the action of acontact-mass consisting of oxides of aluminum and ametal of the groupconsisting of metals having atomic numbers 26, 27 and 28, which areco-precipitate'd in a particular uniform relationship resulting from thefeeding of a solution of salts of said metals and an alkalineprecipitant at rates such that there is a deflciency of the precipitantfor completing precipitation of the metals at any given moment, and

= the subsequent completing of the precipitation of the metals by theaddition of. the deficiency of the precipitant, the aluminum oxide beingin I the predominant proportion.

ROBERT E. BURK. EVERETT C. HUGHES.

